At the time Carlin was relatively well known for tame satirical routines about the entertainment industry. His previous album FM & AM released the same year, showed that he was already drifting towards counter-culture icon, but Class Clown proved a landmark.[according to whom?] Besides musings about his youth, the album featured strongly directed remarks against the Vietnam War and his attachment to taboo topics. The album contains "Seven Words You Can Never Say on Television", which became the focus of government harassment in the year that followed, and, perhaps not coincidentally, Carlin's most famous calling card. Carlin would continue to explore the use of profanity for the rest of his career. Apart from this segment, Class Clown is Carlin's only profanity-free album since 1971.

In the liner notes, Carlin dedicates the album to Lenny Bruce, "for taking all the risks". He also lists all the nuns and priests that worked at Corpus Christi School which he had attended as a child, and who are spoken of at length through the album. In a 2004 appearance on Inside the Actors Studio (episode 1013), Carlin explained that, "I wanted people to know that the disrespect that I had for the dogmatic aspect, and for the inconsistency, and in a lot of cases the cruelty of Catholic doctrine, was tempered with an affection and a gratitude that I had for this wonderful setting that I considered like a garden... where they let me grow... be a creative person and think for myself there, so I kind of wanted to kind of illustrate that, and go, thanks and no thanks".